Two-stroke internal combustion engine



Feb- 28, 1939 A. BQKEMULLER TWO-STROKE INTERNAL COMBUSTIN ENGINE Filed Aug. ll, 1936 2 Sheets-Sheet 1 S .m Il T d@ MM( iffrae/ Feb. 28, 1939. f A. BQKEMULLER 2,148,854

TWO-STROKE INTERNAL COMBUSTIN ENGINE Filed Aug. ll, 1936 2 Sheets-Sheet 2 UNITED STATES PATENT OFFICE TWO-STROKE INTERNAL COMBUSTION ENGINE Alfred Bokemller, Gaggenau, Baden, Germany, assignor to Daimler-Benz Aktiengesellschaft, Stuttgart-Unterturkheim, Germany Application August 11, 1936, Serial No. 95,308 In Germany May 2, 1934 6 Claims. (Cl. 123-65) 'I'he invention concerns an improvement for As generally supercharging is employed with two stroke internal combustion engines and conmedium and smaller numbers of revolutions of sists essentially in a regulating device by which the crankshaft, and, as on the other hand, the the governing angie between the closing moment sections of the scavenging and exhaust time are 6 of the exhaust can be adjusted relatively to the measured for the highest number of revolutions, 5 closing moment of the admission, so that the exthe diminution of the outlet angle with superhaust can be closed either earlier or later than charging is not accompanied by any essential disthe admission, or at the same time as the adadvantages for the scavenging eiect. mission. In Figs. 3 and 4, A is the outlet, and E the in- Accordingly, an object of this invention is the let which is controlled by the piston C acted upon 10 provision of improved means for controlling the by the crank shaft L. The fuel is injected into the exhaust valve of an internal combustion engine, cylinder or, if desired, a precombustion chamber, relative to the ignition, in such a manner that the by means of a nozzle D. exhaust can be closed earlier, simultaneously, or 'I'he outlet A is controlled by a valve V operated later than said ignition. v by an oscillating lever H which, in turn, is con- 15 Another object of this invention is the provision trolled by means of a rod J bearing against the of means for increasing the torque and eiliciency cam shaft N. The lever H is rotatably journaled of an internal combustion engine without superon an eccentric X carried rotatably on the rod W charging. and adjusted by the lever Z. By means of an ad- Further objects and advantages of this inverajustable screw Y, the lever H bears against the 20 tion will be apparent from a consideration of the upper end 0f the IOd J and a Spring V0 hOldS these specification as illustrated by the accompanying parts in positive engaging relationship. By addrawings of possible embodiments of the invenjusting the eccentric X a play is brought about tion, in which drawings: between the lever H and the valve V so that the g5 Fig. 1 is a control diagram illustrating the prinlatter, in accordance with its adjusted position, 25 ciples of this invention; may be opened relatively early or late. By means Fig. 2 is a diagram similarto Fig. 1 but showof such a construction the kind of regulation ing a modified control; shown diagrammaticallyin Fig. 1 is brought about.

Fig. 3 is a cross-sectional view of an internal In the case of the modification shown in Fig. 5,

combustion engine showing an adjustable valve A1 is the outlet, and E1 the inlet controlled by 30 control; the piston Ci. The outlet is controlled by the Fig. 4 is an enlarged view of the adjusting sleeve S which is moved by means of the oscillatmeans illustrated in Fig. 3; ing lever H1, the rod J1, and the cam shaft N1.

Fig. 5 is a. cross-sectional view of an internal The latter is preferably journaled at both ends of combustion engine showing a modified form of the motor in bearings M which are formed as 35 control; sliding members and are transversely shiftable Fig. 6 is an enlarged cross-sectional view of a in the guides O- F01' this Purpose the bearingsv form of inlet control taken along the line 6 6 are provided with threaded spindles P. 'I'he nuts of Fig. 7; and Q threaded upon the spindles and held against 4U Fig. 7 is a side view, partially in cross-section, longitudinal shifting have a worm thread with 40 showing the inlet slide valve and drawnr along which a. worm Wheel POSitiOned 1111011 a IOd Which the line 1-1 of Fig. 6. may be adjustable, for example, by means of the In the drawings, the Figures 1 and 2 show, by lever Z from the drivers seat, engages. By turnway of example, two controlling diagrams, drawn ing the WOI'III rOd by means 0f the level Z Or the with reference to the position o'f the crankshaft. like. the Cam Shaft can be shifted t0 the right 45 The direction of rotation has been indicated by or left and therewith the beginning and end of an arrow. 'I'he angle E is the opening angle of the outlet valve opening can be brOlight about the admittance controlled'e. g. by the piston, sooner or later. The cam shaft is preferably while the opening angle of the exhaust 1s indidriven by means of a chain K tensioned by an o cated at normal running of the engine with A intermediate pulley T acting under the force of 50 and at supercharging running with A. The a spring and connected with the crank shaft L. angle B is shown as the supercharging angle. In In the example shown in Figs. 6 and 7, a rotatcase of Fig. 1 the beginning and the closing of the able sleeve F with control openings F1 is rotatably exhaust is uniformly adjusted; in case oi' Fig. 2, journaled in the attached housing G, and is conhowever, only the exhaust closing is regulated. nected to the inlet Ez through which the cleaning 55 and charged air is easily guided from the suction conductor Ea. The drive is taken from the motor crank shaft by means of a sprocket wheel B. The latter is coupled by means of a key with a socket joint U adjustable in the direction of rotation; the key permits longitudinal shifting. In the 'lnside of the socket joint U there is provided a thread shaped key U1 which engages a corresponding groove U2 of a spindle shaped extension of the rotatable -sleeve F.

A lever Us serves for adjusting the socket joint U in such a manner that by a shifting of the same to the right or to the left a relative turning between the sprocket wheel B and the control sleeve F takes place, resulting in an earlier or later closing off of the inlet.

It will be seen therefore that I have provided l a construction which satisfies the objects enumerated above and while I have shown the invention in certain physical embodiments, it is to be understood that modifications of the structure shown may be made by those skilled in this art without departing from my invention as expressed in the claims which follow.

What I claim is:

1. A two stroke internal combustion engine with an admission and an exhaust device, means operable during operation of the engine for changing the closing time of the exhaust controlled by the exhaust device relatively to the closing time of the admission controlled by the admission device, whereby the said means have such a large range of adjustment that the exhaust can be closed earlier, simultaneously or later than the admission.

2. A two stroke internal combustion engine with ports of admission, controlled bythe piston, and arranged in the lower part of the cylinder, an exhaust device at the upper partof the cylinder, governing means for the exhaust-controlling device, designed to have such a large range of adjustment during operation of the engine that the exhaust can be closed earlier or later than the inlet or simultaneously with the inlet.

3. A two stroke internal combustion engine with admission ports controlled by the piston and ar- -ranged in. the lower part of the cylinder, an

exhaust valvein the cylinder head, a rocking lever for controlling the exhaust valve, the rocking lever supported by an eccentric which has such a large range of adjustment that the exhaust can be closed earlier as Well as later than the admission, or simultaneously with the same.

4. A two stroke internal combustion engine with admission ports, controlled by the piston and arranged in the lower part, of the cylinder, exhaust ports at the upper end of the `cylinder, a

sleeve for controlling the exhaust ports, a cam- 1 shaft for controlling the sleeve, -Which can be means interconnected with said engine for controlling the admission of uids thereto, means interconnected with said engine for controlling the exhaust thereof, and means operable during operation of the engine for adjusting, said last means so constructed and arranged that'said exhaust can be closed earlier, simultaneously, or later than said admission.

6. In an internal combination engine having admission and exhaust ports, means operatively interconnected with said engine for opening and closing said ports, the means for controlling said exhaust port comprising, in combination, a sleeve, a linkage mechanism adapted to oscillate said sleeve, a cam shaft driven by said engine for acting upon said linkage mechanism, bearing means for said cam shaft, and adjustable means for transversely moving said bearing means, whereby the engagement of said cam shaft with said linkagemechanism is varied.

ALFRED BOKEMLLER. 

